Method of producing aldehyde functional multi-component copolymers

ABSTRACT

An aldehyde functional multi-component copolymer is produced by subjecting a multi-component copolymer having olefin bond units in the side chain or in the cyclic group in the main chain to ozonolysis and then reducing the resulting mixed peroxides into aldehyde functional groups. The aldehyde functional multicomponent copolymer is excellent to be used as base material, compounding agent, processing aid and adhesive in rubber industry.

United States Patent [1 1 Yukuta et a1.

l l METHOD OF PRODUCING ALDEHYDE FUNCTIONAL MULTI-COMPONENT COPOLYMERS[75] Inventors: Toshio Yukuta; Takashi Ohashi;

Yoshiko Oguri, all of Tokyo, Japan [73] Assignee: Bridgestone TireCompany Limited,

Kyobashi, Japan 22 Filed: May 23,1972

21 Appl. No.: 256,120

1301 Foreign Application Priority Data Juno 1, 1971 Japan 46-37479 {52]US. Cl. 260/80.78; 260/882 S; 260/877 [51] Int. Cl. C08f 27/22; C08f27/24 158] Field of Search 260/877, 80.78, 88.2 S

[56} References Cited UNITED STATES PATENTS 3.271,477 9/1966 Kresge260/877 3,483,173 12/1969 Natta 260/8078 3,585,174 6/1971 Natta 260/8078FOREIGN PATENTS OR APPLICATIONS 1,347,881 11/1963 France 1,161,8249/1958 France I00 MHZ Accumulation 50fimes Solve/n C684Infernal-reference 77148 J; 9. 76 (ppm) 1 1 June 17, 1975 300,7839/1965' Netherlands 16,911 1965 Japan 26/8 11 OTHER PUBLICATIONS Homerand Jungeleit, Annalen, 1955, 591, 138-148 Lorenz and Parks, J. Org.Chem, 1965, 30, 1976-1981.

Pappas et al., J. Org. Chem, 1968, 33, 787-792. Roberts, John D. andCaserio, Marjorie, pgs. 191-3, Basic Principles of Organic Chemistry,1964, Wv A. Benjamin lnc. Pub1.

Primary Examiner-Joseph L. Schofer Assistant E.raminer-A. L. ClingmanAttorney, Agent, or FirmStevens, Davis, Miller & Mosher [57] ABSTRACT Analdehyde functional multi-component copolymer is produced by subjectinga multi-component copolymer having olefin bond units in the side chainor in the cyclic group in the main chain to ozonolysis and thenreclucing the resulting mixed peroxides into aldehyde functional groups.The aldehyde functional multicomponent copolymer is excellent to be usedas base material, compounding agent, processing aid and adhesive inrubber industry.

9 Claims, 3 Drawing Figures PATENTEDJUN 17 I975 SHEET Q Q Du PATENTEDJUN1 7 ms SHEET umc =Q S mS entucomfiq PATENTEDJUN 17 1975 SHEET 3 mm m w 8Em Bw mmEt Eauuq m QK METHOD OF PRODUCING ALDEHYDE FUNCTIONALMULTl-COMPONENT COPOLYMERS converted into aldehyde functional groups.More particularly, the present invention relates to a method ofproducing aldehyde functional multi-component copolymers having aldehydefunctional groups in the side chain or in the cyclic group in the mainchain, which comprises contacting a multi-component copolymer(hereinafter abridged as multi-component copolymer) having olefin bondunits in the side chain or in the cyclic group in the main chain, whichis prepared from at least two a,B-unsaturated compounds and at least onenon-conjugated diolefin compound, with ozone to effect ozonolysis of theolefin bond units, and then reducing the resulting mixed peroxides witha trivalent phosphorus compound.

Recent progress in the scientific technique demands to develop highpolymers having pertinent properties to the use purpose, and highpolymers having desired properties have been demanded in elastomers. Asthe method for developing novel high polymers by modifying well knownhigh polymers, graft or block copolymerization, formation of derivativesby a chemical reaction, and polymer blending have been effected, butdesired products have often been found difficult to be obtained by thesemethods. For example, in the polymer blending method, there is alimitation in view of the compatibility of polymers to be blended, andthe development of high polymers is hindered by this defeet.

It has recently been found out that ethylene/propyiene copolymer hasrubbery elasticity, and further the property of said copolymer has beenimproved by adding non-conjugated diolefin compound to the copolymer asthe third component to provide cross-linking reactivity to thecopolymer. These ethylene/propylene]- cyclopentadiene or 1,4-hexadienemulti-component copolymers not only have an excellent rubberyelasticity, but also have a high ozone resistance due to absence ofolefin bond units in the main chain. However, these multi-componentcopolymers are still considerably inferior in cross-linking reactivityto general purpose rubbers, such as natural rubber, polyisoprene,polybutadiene and styrene/butadiene copolymer rubber, requirevulcanization at high temperature for a long period of time, and arevery poor in blendability with the general purpose rubbers. Heretofore,in order to improve the serious drawbacks in these multicomponentcopolymers, for example, cross-linking reactivity, blendability,tackiness and adhesivity, various processes have been attempted. Forexample, the following prior arts, wherein the properties of themulticomponent copolymers are improved by utilizing the formation ofderivatives owing to chemical reaction of olefin bond units present inthe side chain or in the cy clic group in the main chain of themulti-component copolymers, have been disclosed.

Use of polyorganohydrosiloxane (Japanese Pat. Application PublicationNo. 13,525/67),

Graft-copolymerization of the copolymer with resinformable monomer(Japanese Pat. Application Publication No. 16,394/68),

Grafting of phosphorus-, sulfuror arsenic series monofunctional acid(Japanese Pat. Application Publication No. 32,423/69),

Formation of natural hardening rubber by means of silane compound(Japanese Pat. Application Publication No. 11,819/70),

Introduction of carboxyl groups by the reaction of the copolymer withdibasicor polybasic acid (Japanese Pat. Application Publication No.20,305/68 and No. 13,59l/70),

Reaction of the copolymer with hydrogenated resin and organic peroxide(Japanese Pat. Application Publication No. 30,942/70),

Grafting of epoxy groups, hydroxy groups, or maleic acid groups(Japanese Pat. Application Publication No. 26,305/68 and U.S. Pat. No.3,448,174 specification 1969)), and

Bromination of the olefin bond units in the side chain (U.S. Pat. No.3,524,826 specification (1970)).

Particularly, the following prior arts utilizing the ozonolysis as inthe present invention have been disclosed. A method of producing graftcopolymers wherein olefin bonds in the side chain of the multicomponentcopolymer are subjected to ozonolysis and then a grafting reaction iseffected in the presence of styrene to graft polystyrene to amulti-component copolymer obtained by the ozonolysis (Japanese Pat.Application Publication No. 16,91 [/65), and a method of producing highmolecular weight carbonyl compounds having carbonyl groups in the sidechain by an oxidation with ozone (Japanese Pat. Application PublicationNo. 16,910/65).

The inventors have already succeeded in the production of aldehydefunctional polymers having a molecular weight of 500 to 50,000 andhaving aldehyde functional groups at least at the both ends of moleculeby subjecting a polymer having olefin bond units in the main chain tooxonolysis, and then reducing the resulting product with a trivalentphosphorus compound. The inventors further continued the investigationand reached the present invention. As the polymer having aldehydefunctional groups in the side chain, homopolymer and copolymer ofacrolein have hitherto been known. However, methods for producingmulticomponent copolymers having aldehyde functional groups in the sidechain have never been known. According to the method of the presentinvention it has been able to obtain a modified multi-componentcopolymer having novel properties, which have never been obtainedheretofore, from a well-known multicomponent copolymer containing anon-conjugated diolefin compound as the third component by convertingthe olefin bond units into aldehyde functional groups regardless of thekind of the non-conjugated diolefin compound. The thus obtained modifiedmulticomponent copolymer of the present invention has novel propertiesdue to the aldehyde functional groups. Accordingly, the modifiedcopolymer is a useful industrial material and can be used as basematerial for elastomer, base material for oil extended elastomer,compounding ingredient or processing aid for other elastomers, basematerial of liquid rubber and resin, and adhesive.

The multi-component copolymers to be used in the present invention areproduced from at least two afi-unsaturated compounds and at least onenonconjugated diolefin compound. The a,B-unsaturated the otherafi-unsaturated compound, for example, propylene, and another doublebond remains in the side chain or in the cyclic group in the main chainand contributes to the unsaturation property and the crosscompounds areones having 2 to 8 carbon atoms, u 5 linking reactivity of the EPDM. Thepresent invention as ethylen pr pyl ne and the like- The relates to theozonolysis of the olefin bond remaining C(JnjUgflIed (Olefin Compoundsinclude straightin the EPDM molecule and to the reduction of the Chainalip atic diEnBS, Such as 1,4-heXEldiefle, mixed peroxides obtained bythe above ozonolysis into hexadiene, 1,6-octadiene and the like; (b)branched ald h d functional groups.

C ai aliphatic dienes. Such as 5-methyl4 .4-h6Xi1dienB The fundamentalresearch of the oxidation reaction ime hy fi-Octildiehe, y -L of ozoneagainst organic compounds was completed in tadi nd the like; monocychcahcydic dienes, the beginning of the 20th century by the wide investiga-Such as "-y lj'clclooctadifinei tion of Harries. Later, a large numberof fundamental cyclododecadlenei twinylcyclohexene, y researchesrelating to the ozonolysis of double bonds lSOPYOPYlldcnecyclohexanei3'allylcyclopemene' 15 has been reported. Among them, the most commonlyallylcyclohexenfi supported reaction mechanism in the ozonolysis is thebutenyncyclohexane and the like; and (d) Polycychc zwitter-ion theory byCriegee (R. Criegee, Rec. Chem. alicyclic dienes, such astetrahydroindene, methyltetprogr. 13 111 1957 d h reaction mechanismfahydl'oindene dlcyclopemadienet y in the zwitter-ion theory is asfollows.

)c c +o )c 0+ -c l HS (solvent) I (|)-O e O-O-H hydrogen peroxidecompound (2,2,l )hepta-2,5-diene, alkenyl-, alkylidene-, cycloalkenylandcycloalkylidene-norbornene, such as S-methylenenorbornene,S-ethylidenenorbornene, 5-propenylnorbornene,5-isopropylidenenorbornene, 5-(4-cyclopentenyl)norbornene,S-cyclohexylidenenorbornene and the like. However, the non-conjugateddiolefin compounds are not limited to these dienes.

A preferred multi-component copolymer to be used in the presentinvention is a terpolymer prepared from ethylene, propylene and anon-conjugated diolefin compound, and is usually called as EPDM. Thecomposition ratio of monomers constituting the EPDM is not particularlylimited. and to 85 mol% of ethylene, l5 to 70 mol% of propylene and L0to l0 mol% of a nonconjugated diolefin compound are generally used.Further, the molecular weight of the EPDM is not particularly limited,and liquid EPDM or EPDM having a number average molecular weight of350,000 is used depending upon the purpose. The preparation method ofthe EPDM is disclosed in various patent specifications, for example, inUS. Pat. Nos. 2,933,480, 3,000,866 and 3,093,621 specifications.

It is generally considered that one of the double bonds contained in themolecule of the non-conjugated diolefin compound, which is the thirdcomponent constituting the EPDM, serves to form a terpolymer of thenon-conjugated diolefin compound with ethylene and 0-0 \C/ \C/ \C/oxonide peroxide That is, the ozonolysis of double bond produces mixedperoxides of hydrogen peroxide compound, ozonide and peroxide havingvarious mixture ratios of these components depending upon the reactioncondition through an unstable zwitter-ion as one intermediate product.The thus formed mixed peroxides can be converted into carboxylic acids,aldehydes, ketones, alcohols and other compounds by oxidation,reduction, hy-

drolysis or pyrolysis depending upon the purpose. As

hydrogen atom is bonded to the olefinic carbon of the starting material,the thus formed intermediate compound is aldehyde. The present inventionconsists in a method of a novel modified multi-component copolymer,wherein all the mixed peroxides obtained by. the

ozonolysis are converted into substantially aldehyde functional groupsby reduction treatment. The ratio of olefin bond units converted intoaldehyde functional groups can be selected optionally by regulatingamounts of ozone depending upon the purpose, and the ,5 ratio is notparticularly limited. The resulting aldehyde functional multi-componentcopolymer preserves physical properties of the multi-componentcopolymer, which is used as the starting material for said aldehydefunctional multi-component copolymer. and accordingly any desiredcopolymers from liquid low molecular weight moldable copolymer to highmolecular weight rubbery elastomer can be produced by selecting themulti-component copolymer to be used.

In the present invention, the starting multicomponent copolymer selecteddepending upon the purpose is dissolved in a proper solvent. As thesolvent, mention may be made of those which are inert to ozone, forexample, halogenated hydrocarbons, such as carbon tetrachloride,chloroform. methylene chloride and the like; aliphatic or cyclic ethers.such as ether, tetrahydrofuran. dioxane and the like; aromatichydrocarbons, such as benzene, toluene, mixed xylene and the like; andaliphatic hydrocarbons, such as pentane, hexane. heptane and the like.In a particular case, alcohols, acids, acid anhydrides and esters may beused. However, the solvent is not limited to the above describedsolvents. Halogenated hydrocarbons are generally preferable, and amongthem, chloroform and methylene chloride are particularly preferable. Theamount of the solvent to be used is optional, but has a relation to thegelation in the ozonolysis, and is preferred to make the concentrationof the multicomponent copolymer in the solvent as far as low. Ingeneral, the concentration of the solution is preferably 0.1 g/l00 ml to50 g/l()() ml, and in particular preferably l g/l00 ml to g/l00 ml.

In the present invention, ozone is generally used in the form of agaseous mixture with a carrier gas se lected from air or oxygen. Theconcentration of ozone in air or in oxygen and the addition amount ofozone can be selected within a wide range. By selecting a condition forgenerating ozone corresponding to the iodine value of multi-componentcopolymers, which is measure of the amount of olefin bonds of thecopolymers, aldehyde functional multi-component copolymers containingdesired amount of aldehyde functional groups can be produced. It isgenerally preferable to use a gaseous mixture containing ozone in aconcentration as low as possible. That is, the amount of ozone ispreferably not more than 0.5% and not less than 0.l7r by weight based onthe carrier gas (that is. not more than 6 mg per l l ofthe carrier gas).and particularly preferably not more than 0.2% and not less than 0.1% byweight based on the carrier gas. The ozonolysis of the multi-componentcopolymer is carried out by blowing a gaseous mixture containing ozonethrough a solution of the copolymer in a proper solvent while stirring.

The ozonolysis temperature can be selected optionally within the rangeof 80 to +60C, and a preferable temperature range is to +40C, andparticularly preferable temperature range is -l5 to +20C.

The contacting time of the multi-component copolymer with ozone in theozonolysis has an intimate relation to the amount of olefin bondscontained in the multi-component copolymer and to the desired amount ofaldehyde functional groups corresponding to the amount of the olefinbonds. In general, the contacting time is within the range of 0.5 to 24hours. The mixed peroxides obtained by the above described ozonolysis ofthe muIti-component copolymer are directly subjected to the nextreduction treatment.

In the present invention. the mixed peroxides ob tained by theozonolysis of the multi-component copolymer are com erted into aldehydefunctional groups by the use of a proper reducing agent. The solvents tobe used in the reduction reaction may be ones which can be used in theozonolysis and dissolve the mixed peroxides obtained by the ozonolysis,and can proceed smoothly the reduction reaction. That is, in general,the solvent used in the ozonolysis is directly used in the reductionreaction. Otherwise, the solvent is evaporated after the ozonolysis. andthen a proper solvent or a mixed solvent may be used. The inventors havemade specifically various investigations with respect to the reducingagents which have been used in conventional reduction methods, and foundreducing agents capable of reducing effectively the mixed peroxidesobtained by the ozonolysis of the multi-component copolymer intoaldehyde functional groups, and reached a method of producing aldehydefunctional multi-component copolymers. It has been well known that anexcellent method of directly reducing mixed peroxides obtained by theozonolysis of a low molecular weight compound into aldehyde functionalgroup utilizes the reactivity of nucleophilic reagents, such asnitrogen, phosphorus and sulfur compounds, with compounds containingactive oxygen (Edited by R. L. Augustin, "Oxidation", Technique andApplication in Organic Synthesis, Vol. 1, Marcel Dekker, Inc. N.Y.,1969).

The reducing agents to be used in the present invention are trivalentphosphorus compounds. The present invention utilizes the reducing powerof trivalent phosphorus atom which is caused when trivalent phosphorusatom is oxidized into pentavalent phosphorus atom by the reaction withactive oxygen. As the reducing agent, mention may be made oftriphenylphosphine, triethyl phosphite, tris-(dimethylamino)phosphine,and the like. However, these compounds are not limitative. Among thesecompounds, triphenylphosphine is particularly preferable.

The reducing agent is generally used in an excess amount, that is, in anamount of 0.5 to 3.0 equivalents, preferably L2 to 2.0 equivalents,based on the equivalent of the mixed peroxides obtained by theozonolysis. The reaction temperature and time in the reduction can beselected optionally. In general, the reduction is completedquantitatively when the reaction mixture is left to stand at roomtemperature for several days, or when the reaction mixture is heated at50 to C for several hours under stirring and reflux. After comple tionof the reduction, the solvent is evaporated, and a proper solvent, forexample, acetone, which does not dissolve the resulting aldehydefunctional multicomponent copolymer but dissolves unreacted excessamount of the reducing agent and its oxide, is newly added to thereaction mass to purify the aldehyde functional multi-componentcopolymer. However, the purification process in the after-treatment canbe selected optionally.

For a better understanding of the invention, refer ence is taken to theaccompanying drawings, wherein:

FIG. 1 is an infrared absorption spectrum of the EPDM terpolymer to beused as a starting material in Example I of the present invention,

FIG. 2 is an infrared absorption spectrum of the aldehyde functionalEPDM terpolymer obtained in Exam' ple l of the present invention; and

FIG. 3 is a nuclear magnetic resonance spectrum due to the aldehydefunctional groups of the aldehyde functional EPDM terpolymer obtained inExample 1 of the present invention.

The following example is given in illustration of this invention and isnot intended as a limitation thereof.

EXAMPLE l ln 4 l of chloroform was dissolved 50 g of EPDM Nordel 1070(trademark of ethylene/propylene/l .4- hexadiene copolymer made by AsahiKasei K.K., propylene content is 34 mol% and l.4-hexadiene content is1.6 mol% based on the total moles of ethylene and propylene, and gelcontent is 5.8% by weight), and the gel was filtered off by means of awire gauze. The filtrate was introduced into a 4 neck separable flask ofl capacity equipped with a stirrer driven by a motor and a Dewarcondenser, and ozone was introduced into the flask through a glass ballfilter while the solution was stirred vigorously at room temperature.Ozone was generated from oxygen by means of an 0-l-2 type ozonegenerator made by Nippon Ozone K.K. Ozone was introduced into the flasktogether with oxygen under such a condition that the flow rate of oxygenwas kept at 2.5 l/min, and oxygen having an ozone content of 2 mg/l wasflowed during the first 4 hours, and oxygen having an ozone content ofmg/l was flowed during the next 40 minutes, whereby a total amount of2.2 g of ozone was introduced into the flask. After introduction ofozone was completed, the reaction solution was bubbled wholly with driednitrogen at a rate of 3 l/min for 2 hours to remove residual oxygen Asolution of l2.l g of triphenylphosphine in 500 ml of chloroform wasadded to the solution containing mixed peroxides obtained by the abovedescribed ozonolysis by means of a dropping funnel equipped with apressure balancing side tube, and the resulting mass was refluxed for 2hours at a bath temperature of about 65C while stirring. and then leftto stand until the mass was cooled to room temperature. Major part ofthe chloroform was evaporated by means of a rotary evaporater to obtaina viscous solution of a crude aldehyde functional EPDM terpolymer inchloroform. Then, the viscous solution was poured into acetone, andafter the resulting mass was stirred, the reaction product wasprecipitated. The precipitate was dried in a conventional manner toobtain 42 g of a purified aldehyde functional EPDM terpolymer.

FIG. 2 shows the infrared absorption spectrum of the thus obtainedterpolymer. In this spectrum, an absorption at 952 cm, which is one ofabsorptions assigned to the starting EPDM Nordel 1070 and is due to thedouble bond of 1,4-hexadiene used as the third component (refer to FIG.1), is diminished, absorptions at 1725 cm and 2700 cm due to thealdehyde functional groups are newly formed, absorptions at l7l0 cm and2650 cm inherent to the carboxyl group can be neglected, and anabsorption due to the hydroxyl groups is not present. Accordingly, thisspectrum proves that aldehyde functional EPDM terpolymers containingsubstantially only aldehyde functional groups are produced according tothe present invention.

FIG. 3 shows the nuclear magnetic resonance spectrum of the sameterpolymer. In this spectrum, an absorption inherent to the proton ofthe aldehyde functional group is present at a chemical shift of 5 9.76(ppm). Accordingly, this spectrum also proves that aldehyde functionalEPDM terpolymers are produced according to the present invention.

What is claimed is:

1. An aldehyde functional multi-component copolymer having aldehydefunctional groups in the side chain or in the cyclic group in the mainchain, which is obtained by subjecting a multi-component copolymercomposed of 30-85 mol% of ethylene, 15-70 mol% of propylene and l-lOmol% of at least one nonconjugated diene compound to an ozonolysis in asolvent at a temperature of C to +60C with ozone mixed with a carriergas in a concentration of 0.1 to 0.5% by weight based on the weight ofthe carrier gas, and then reducing the resulting mixed peroxides formedby ozonolysis of olefin bond units with a trivalent phosphorus compoundin an amount of 0.5 to 3.0 equivalents based on the equivalent of themixed peroxides.

2. The product as claimed in claim 1, wherein said multi-componentcopolymer is EPDM composed of ethylene, propylene and 1,4-hexadiene.

3. The product as claimed in claim 1, wherein said solvent is at leastone member selected from the group consisting of halogenatedhydrocarbons, aliphatic or cyclic ethers, aromatic hydrocarbons andaliphatic hydrocarbons.

4. The product as claimed in claim 1, wherein the ozonolysis temperatureis within the range of 30" to +40C.

5. The product as claimed in claim 1, wherein said trivalent phosphoruscompound to be used as a reducing agent is used in an amount of 1.2 to2.0 equivalents based on the equivalent of the mixed peroxides obtainedby the ozonolysis.

6. The product as claimed in claim 1, wherein said trivalent phosphoruscompound is selected from the group consisting of triphenylphosphine,triethylphosphite anad tris-(dimethylamino)phosphine.

7. The product as claimed in claim 1, wherein said solvent is at leastone member selected from the group consisting of carbon tetrachloride,chloroform and methylene chloride.

8. The product as claimed in claim 1, wherein the ozonolysis temperatureis within the range of -15 to +20C.

9. The product as claimed in claim 5, wherein said trivalent phosphoruscompound is triphenylphosphine. a:

1. AN ALDEHYDE FUNCTIONAL MULTI-COMPONENT COPOLYMER HAVING ALDEHYDEFUNCTIONAL GROUPS IN THE SIDE CHAIN OR IN THE CYCLIC GROUP IN THE MAIBCHAIN, WHICH IS OBTAINED BY SUBJECTING A MULTI-COMPONENT COPOLYMERCOMPOSED OF 30-85 MOL % OF ETHYLENE, 15-70 MOL % OF PROPYLENE AND 1-10MOL % OF AT LEAST ONE NON-CONJUGATED DIENE COMPOUND TO AN OZONOLYSIS INA SOLVENT
 2. The product as claimed in claim 1, wherein saidmulti-component copolymer is EPDM composed of ethylene, propylene and1,4-hexadiene.
 3. The product as claimed in claim 1, wherein saidsolvent is at least one member selected from the group consisting ofhalogenated hydrocarbons, aliphatic or cyclic ethers, aromatichydrocarbons and aliphatic hydrocarbons.
 4. The product as claimed inclaim 1, wherein the ozonolysis temperature is within the range of -30*to +40*C.
 5. The product as claimed in claim 1, wherein said trivalentphosphorus compound to be used as a reducing agent is used in an amountof 1.2 to 2.0 equivalents based on the equivalent of the mixed peroxidesobtained by the ozonolysis.
 6. The product as claimed in claim 1,wherein said trivalent phosphorus compound is selected from the groupconsisting of triphenylphosphine, triethylphosphite anadtris-(dimethylamino)phosphine.
 7. The product as claimed in claim 1,wherein said solvent is at least one member selected from the groupconsisting of carbon tetrachloride, chloroform and methylene chloride.8. The product as claimed in claim 1, wherein the ozonolysis temperatureis within the range of -15* to +20*C.
 9. The product as claimed in claim5, wherein said trivalent phosphorus compound is triphenylphosphine.